1. Field of the Invention
The present invention relates to a method and related apparatus for chip testing, and more particularly, a method and related apparatus for chip testing capable of differentiating whether or not each analogue front-end of a digital/analogue circuit inside a chip functions as normal.
2. Description of the Prior Art
An electronic circuit is an extremely important hardware foundation in our modernized information society; as semiconductor information industry develops, electronic circuits of different functions have been integrated into a single chip, resulting in the single chip having many complicated functions.
In order for the chip to operate normally, it is necessary to carry out a test on the manufactured chip. However, in present chip test technology, emphasis is placed on the overall function of the chip. In the most basic test, the chip is tested for corresponding reactions under predetermined conditions according to specification and function based on the chip design—for example, how the chip should respond and what signals are transmitted after the chip receives or executes a specific signal/instruction. An actual test is then applied to the chip in receiving or executing this kind of signal/instruction, and the chip is checked as to whether the response sent out conforms to the standard required. This is in order to understand whether the operation of the chip conforms to the specification and the function of the original design.
Although the above mentioned prior art is capable of determining whether the overall function of the finished product (chip) is functioning normally, when the chip is not functioning normally, this test technology is unable to determine which part of the chip is not operating. As mentioned previously, the modern chip has many kinds of complicated integrated electronic circuits, therefore if the abnormal part in the chip cannot be clearly located, tests engineers will have difficulty in determining the reason for the fault. For example, most modern chips have digital input/output circuits and analogue transmission/receiving circuits; after the chip performs a digital processing operation, signals to be sent out will be converted into a predetermined format via the output circuit, and then activated and transmitted by the transmission circuit. The signal to be transmitted to the chip is first sensed by a receiving circuit, and inverse-converted by the input circuit to form digital signals that can be read/processed by the chip. When testing the chip, if signals sent out by the chip do not conform to a response which the chip should have, there is a possibility that digital input/output circuits are not functioning normally, or there is a possibility that the function of an analogue transmission/receiving circuit is abnormal. The prior art can only observe and compare the whole output of the chip, and the exact location of the malfunction circuit cannot be distinguished, this also causes the chip manufacturers difficulties in effectively improving chip design or production technology.